1. Field of the Invention
This invention relates to a magnetic recording medium. More particularly, this invention relates to a magnetic recording medium with outstanding surface and high electromagnetic properties produced by blending a radiation curable resin obtained by modifying a copolymer of vinyl chloride, a vinyl carboxylate, vinyl alcohol, an unsaturated carboxylic acid and a carboxylic anhydride, and other polymer and a magnetic powder, applying the resultant magnetic paint to a nonmagnetic substrate, and curing the applied layer of paint with radiation.
2. Description of Prior Art
Magnetic recording media are used extensively in the form of magnetic tapes for audio and video recording, magnetic disks for computers and word processors, and magnetic cards for other household appliances, for examples. In the production of such magetic recording media, the practice of effecting fast adhesion of magnetic powder formulations to their substrates by using a radiation-sensitive curing resin as a binder and crosslinking and polymerizing this binder with radiation is now in vogue.
Magnetic recording media using the aforementioned radiation curable resin as the binder, however, have suffered from the disadvantages that they have high friction coefficients and are still deficient in surface properties such as gloss, orienting properties and electromagnetic properties. As a solution to these disadvantages, we previously described a resin solution for magnetic paint having as a main component thereof a copolymer of (A) vinyl chloride, (B) a vinyl carboxylate, (C) an unsaturated carboxylic acid and (D) an unsaturated carboxylic anhydride, containing 50 to 80% by weight of (A) based on the total of the amounts of (A) and (B), 0 to 30% by weight of (E) based on the total of the amounts of (D) and (E), and 1 to 5 parts by weight of the total of (D) and (E) based on 100 parts by weight of the total of (A) and (B) and having an average polymerization degree of 100 to 400 (Japanese Patent Open No. SHO 57(1982)-128,711). The magnetic recording media using the solution mentioned above, however, are still unsatisfactory in terms of friction coefficient, gloss, orienting property, electromagnetic property, etc.
An object of this invention, therefore, is to provide an improved magnetic recording medium.
Another object of this invention is to provide a magnetic recording medium which has a low friction coefficient and is excellent in surface, orienting and electro-magnetic properties.